基于模糊理论的加速度计标度因数稳定性分析

运用模糊理论描述了影响加速度计标度因数稳定性诸多因素的不确定性问题,针对其中的磁钢磁感应强度和石英摆片热膨胀系数两类稳定性影响因素,给出了其三角模糊数区间,并通过该型加速度计的磁-结构耦合ANSYS分析求出了在模糊参数不同组合下的仿真输出,根据仿真输出结果获得了标度因数模糊稳定区间,给出了加速度计标度因数稳定性分析流程及实例.分析说明了基于模糊理论的稳定性分析方法可以为加速度计加速稳定试验截止条件提供依据,对提高加速度计标度因数长期稳定性水平具有重要意义.     

运动补偿用惯性器件误差对SAR成像分辨率的影响研究

 为提高合成孔径雷达（SAR）系统的性价比,必须根据SAR成像分辨率的要求和整体系统参数,设计相应精度的运动补偿用捷联惯导系统。在确定SAR运动补偿系统方案和安装方式的基础上,分析不同方向的加速度计和陀螺仪误差对天线相位中心位置测量误差的影响,并利用位置测量误差与SAR成像分辨率之间的关系,进一步明确了不同方向的加速度计和陀螺仪对SAR成像分辨率的影响。研究表明：基于SAR的工作原理和安装方式,x方向加速度计和y方向陀螺仪对SAR成像分辨率的影响明显比其他惯性器件严重;相同误差水平的惯性器件对SAR成像分辨率的影响随着合成孔径时间和工作波长的不同而不同,时间越长,波长越短,影响则越严重。SAR成像仿真证明了结论的正确性。研究结果对于研制高性价比SAR成像运动补偿系统有一定的理论指导意义。     

基于两级应力隔离的MEMS加速度计封装设计

封装应力是影响MEMS加速度计性能尤其是温度特性的关键因素之一.为降低封装应力,提出了一种两级应力隔离的低应力封装设计,包含芯片级应力隔离和封装级应力缓冲.采用有限元仿真模拟了四种封装设计和四种粘片方式.仿真结果表明,芯片级应力隔离比封装级应力缓冲效果更好,采用两级应力隔离可以将敏感电容的温度特性改善8倍,且四点胶粘片...     

利用车载试验分离惯导平台误差研究

分析了车载试验时平台的安装方式以及所需要的外测信号等问题,给出了误差模型以及导航误差方程,设计并进行相关软件仿真。结果表明,在现有外测信号精度下,该方法可分离出惯导平台误差中加速度计和陀螺仪的零次项误差系数,对加速度计的一次项误差系数分离效果也较好。     

基于神经网络的加速度计静态误差系数标定

利用具有强自学习性、自适应能力及非线性变换特性的神经网络方法，构造加速度计静态函数型神经网络模型，并用于对加速度计静态误差系数的标定。试验证明，利用该方法标定的系数结果具有高精度性，可较好地满足加速度计误差补偿的要求。     

高分辨率雷达中带宽对信号检测影响的研究

利用单脉冲单元平均恒虚警（CA-CFAR）滑窗检测方法，对不同波段高分辨率雷达（VHF和l波段）的实测数据进行了目标检测仿真，并分析了雷达绝对带宽与相对带宽对信号检测的影响。结果表明，波段选择对信号检测影响较小，绝对带宽对信号检测影响较大。检测概率为90％时，带宽25MHz和200MHz的所需输入信噪比相差5dB。在能量一定的情况下，高分辨率雷达的检测性能优于低分辨率雷达。     

Unbiased acceleration measurements with an electrostatic accelerometer on a rotating platform

The Gravity Advanced Package is an instrument composed of an electrostatic accelerometer called MicroSTAR and a rotating platform called Bias Rejection System. It aims at measuring with no bias the non-gravitational acceleration of a spacecraft. It is envisioned to be embarked on an interplanetary spacecraft as a tool to test the laws of gravitation.     

Free fall tests of the accelerometers of the MICROSCOPE mission

The MICROSCOPE mission is fully dedicated to the in-orbit test of the Universality of free fall, the so-called Weak Equivalence Principle (WEP), with an expected accuracy better than 10⁻¹⁵. The test principle consists in comparing the accelerations of two proof masses of different composition in the Earth gravitational field. The payload embarks two pairs of test-masses made of Platinum Rhodium and Titanium alloys at the core of two dedicated coaxial electrostatic accelerometers. These instruments are under qualification for a launch in 2016.     

Impact of a novel hybrid accelerometer on satellite gravimetry performance

The state-of-the-art electrostatic accelerometers (EA) used for the retrieval of non-gravitational forces acting on a satellite constitute a core component of every dedicated gravity field mission. However, due to their difficult-to-control thermal drift in the low observation frequencies, they are also one of the most limiting factors of the achievable performance of gravity recovery. Recently, a hybrid accelerometer consisting of a regular EA and a novel cold atom interferometer (CAI) that features a time-invariant observation stability and constantly recalibrates the EA has been developed in order to remedy this major drawback. In this paper we aim to assess the value of the hybrid accelerometer for gravity field retrieval in the context of GRACE-type and Bender-type missions by means of numerical closed-loop simulations where possible noise specifications of the novel instrument are considered and different components of the Earth’s gravity field signal are added subsequently. It is shown that the quality of the gravity field solutions is mainly dependent on the CAI’s measurement accuracy. While a low CAI performance (10^?8 to 10^?9?m/s²/Hz^1/2) does not lead to any gains compared to a stand-alone EA, a sufficiently high one (10^?11?m/s²/Hz^1/2) may improve the retrieval performance by over one order of magnitude. We also show that improvements which are limited to low-frequency observations may even propagate into high spherical harmonic degrees. Further, the accelerometer performance seems to play a less prominent role if the overall observation geometry is improved as it is the case for a Bender-type mission. The impact of the accelerometer measurements diminishes further when temporal variations of the gravity field are introduced, pointing out the need for proper de-aliasing techniques. An additional study reveals that the hybrid accelerometer is – contrary to a stand-alone EA – widely unaffected by scale factor instabilities.     

随机编码感知的高分辨遥感光谱计算成像

传统遥感光谱成像系统的空间分辨率和光谱分辨率是衡量成像品质的重要指标,而它们受制于探测传感器的点阵密度,提高遥感光谱成像传感器的性能代价非常巨大。另一方面,在入射光能量一定的条件下,由于高分辨光谱的窄波段成像与低窄带辐射能量接收之间的矛盾,传统遥感光谱成像方法的空间分辨率和光谱分辨率往往难以兼得。如何利用普通探测器获得...